The present invention relates to a fastener for window inserts or grids for removably attaching window inserts or grids to the sashes of windows.
Conventional windows used extensively in the construction industry generally comprise a single pane of glass carried peripherally by a window sash. It is particularly desirable at times to make the window pane appear to be comprised of a plurality of window panes carried adjacent to one another. In order to accomplish this effect, lattice window inserts often are installed adjacent window panes with the ends of the lattice strips being attached to the sash.
Several fastening methods have been employed in the past to attach lattice window inserts to window sashes. One such method, exemplified by U.S. Pat. No. 5,109,647, employs a metal clip formed of spring metal and including a frame engaging leg and a coupling leg. The frame engaging leg of each clip is secured to the window frame. The coupling leg in one embodiment has an outwardly convex outer surface which engages an angular recess in the insert with a snap coupling spring effect. In another embodiment, the coupling leg includes a rolled portion which engages an arcuate recess in the insert bar with a spring coupling action. However, it has been found that the metal grille clips in the '647 patent are difficult for the average consumer to install. Further, when the insert is removed so that the window pane can be cleaned, the grille clips are frequently misplaced or lost. In addition it has been experienced that during the installation of the spring metal grille clips between the window sash and the glass pane a stress crack condition on the glass will be created.
Another method is illustrated by U.S. Pat. No. 3,221,462. In this patent, there is disclosed a sliding fastener that is slidable in a passageway in the insert or grid, the fastener having a head that projects beyond the insert or grid into an opening in the window casement. The disadvantage of this arrangement is that the fastener must be accessible from outside the grid in order to manipulate the fastener. Thus, the fastener cannot be readily concealed within the grid, and may present an unsightly appearance.
Still another method is illustrated by U.S. Pat. No. 4,838,001, in which there is disclosed a window grid latch comprising a housing with an internal spring means that biases a pin into an opening in the window frame. A finger operated handle is used to slide the pin into and out of the housing. As in the '462 patent, the latch thus cannot be readily concealed in the window grid, presenting an unsightly appearance. The device is also complex, requiring a separate spring and an internal latch in the housing to retain the pin in the retracted position.
Another complex device for fastening a window grid to a window frame is shown in U.S. Pat. No. 5,437,133. This is a multi-piece part with a spring-loaded plunger assembly and a base portion movably secured to the plunger assembly. Exact molding of the parts is necessary to make sure that the plunger assembly can engage a radial shoulder on the base by means of a mating flange on the plunger assembly. The coil spring is a separate part and must be installed into the base and plunger. It appears that the coil spring or the plunger may break after repeated use, making the fastener unusable.
There is a need for a simple, inexpensive, one-piece window insert fastener that does not require an external handle to operate, is readily concealable within the window insert, and which is not readily lost when the window insert is removed to clean the window.